Given below are two statements: Statement I: Amino acids have a property of ionizable nature of –NH2 and –COOH groups, hence have different structures at different pH. Statement II: Amino acids can exist as Zwitterionic form at acidic and basic pH. In the light of the above statements, choose the most appropriate answer from the options given below:
Both Statement I and Statement II are correct.
Both Statement I and Statement II are incorrect.
Statement I is correct but Statement II is incorrect.
Statement I is incorrect but Statement II is correct.
Statement I is correct because amino acids possess a particular property involving the ionizable nature of –NH2 and –COOH groups, which causes their structure to change in solutions of different pH . Statement II is incorrect because the Zwitterionic form (a dipolar ion where the amino acid carries both a positive and negative charge but is electrically neutral) is pH-dependent . In acidic pH (high H+ concentration), the carboxyl group (COO-) accepts a proton to become COOH, making the molecule a cation; in basic pH (low H+ concentration), the amino group (NH3+) loses a proton to become NH2, making the molecule an anion [outside of sources]. Thus, the Zwitterionic form exists primarily at a specific pH (the isoelectric point) rather than at any acidic or basic pH .
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